1. Technical Field
The present invention is in the field of metal container manufacturing, and more specifically in the field of metal containers adapted to dispense a pressurized or aerosol product.
2. Introduction
Metal cans and containers have long been used to hold and dispense a wide variety of goods and materials, in solid, liquid, or gaseous forms. When used to hold an aerosol product, the metal containers are designed to withstand pressure fluctuations caused by external factors such as temperature variations. Such containers may also be subjected to large mechanical stresses and pressure spikes caused by drops and other sudden impacts, providing a further design consideration. Depending on the intended application of the metal container, a combination of qualities is required. Such qualities might include cost, durability, strength, and manufacturing speed.
The most common type of metal container is formed from a flat metal disc, usually aluminum, which is stretched into a cup-like shape through an inelastic process known as drawing and ironing. A pre-formed metal top is then attached to complete the container. For use in low-pressure applications, drawn metal containers are desirable because of their low cost and high speed of manufacture. Drawn metal containers are most commonly used to hold carbonated beverages. However, these drawn containers have thin walls that are subject to variance in thickness and are more prone to burst and fail at higher pressures or when subjected to impacts or drops.
Rolled metal containers are also available, wherein a flat piece of sheet metal, usually steel, is formed into a cylinder, and base and top components are each attached via crimped seams to the cylindrical sidewall to complete the container. These containers have a more consistent wall thickness than drawn containers, and because they are less likely to suffer burst failures at high pressures, are most commonly used in higher-pressure (e.g. aerosol) applications. However, the top and bottom crimped seams make the container heavy and cause a greater probability of failure from impacts or drops when compared to a drawn container.
Thus there is an ongoing need for a metal container, particularly in aerosol applications, that can be manufactured to withstand high pressure and failure from impacts and drops, while minimizing the number of crimped seams required.